Corer for turbine driven well drilling units



H. BON I 2,910,273

CORER FOR TURBINE DRIVEN WELL DRILLING uun's Oct. 27, 1959 Filed Jan. 18, 1957 Wm W INVENTOR HE NR/ BON ATTORNEY UnitedStates Patent CORER FOR TURBINE DRIVEN WELL DRILLING UNITS Henri Bon, Grenoble, France, assignor to Etablissements I drilling wells, and more particularly to improvements in the arrangements whereby a turbine driven coring bit may be used to produce a core and in the means cooperative therewith for extracting the core.

During a drilling operation, when it is necessary to remove a sample of earth known as a core the conventional drilling bit is replaced by a coring bit provided with a central orifice which in the course of the drilling operation leaves a cylinder of the rock or earth formation being penetrated. This constitutes the core.

In order to remove this core there is mounted within the turbine shaft a removable coring tube. In one known form of turbo-corer this coring tube is provided with a plug at its upper end having a tapered body which rests tightly on a seat in order to prevent any penetration of the circulating fiuid or drilling mud to the interior 'of the coring tube. member is formed in a fixed member connected to the stationary member of the turbine unit so that during the coring operation the coring tube is held in a fixed relation to the turbine.

At its lower end the coring tube is provided with suitable means, such as spring pressed ratchets, arranged to engage the core and aid in tearing it loose from the earth formation of which it was a part, and to retain or hold the core inside of the tube when the coring tube is lifted upwardly away from the turbinethrough the drill pipe.

Since in turbodrilling reliance is had upon a suitable fluid drilling mud for operating the turbine, it will be understood that when a core is to be taken and the turbocorer is attached to the drill pipe and lowered into the drill hole for such purpose, the drilling mud present in the drill hole will at the start pass up into the coring tube and fill the same, in this way hampering or preventing the core of the earth formation from entering the coring tube unless some way is provided for the escape of the entrapped mud from the coring tube.

The arrangement adapted for this purpose up until now has consisted in putting the interior space of the coring tube into communication at a suitable level with the annular space between it and the rotor shaft of the turbine by means of a drainage valve. Since the pressure in this annular space will normally be close to that of the drilling mud at the entrance to the turbine; that is .to say, the hydrostatic pressure of the column of mud increased by the additional pressure imposed on the column by suitable pumping means to maintain the pressure required to operate the turbine, it will be understood that there remains a very considerable resistance to the escape of the mud initially entrapped in the coring tube with resultant opposition to penetration of the core into the coring tube.

The present invention has for an object to remedy this difficulty by reducing as far as possible the pressure on the drilling mud present at the start of the coring operation in the coring tube. This is accomplished by The seat for the plug putting the interior of the coring tube into communication with the annular space between the outside of the turbo-corer unit and the wall of the bore hole being drilled. the drilling mud at the top of the coring tube is only approximately the same as the hydrostatic pressure on the column of mud in the annular space between the drill pipe and the wall of the drill hole. As this pressure is far below that prevailing within the drill pipe above the turbine blades, which may be augmented for operation of the turbine by several hundred p.s.i. as compared to 'the hydrostatic pressure of the column or" mud alone, the core easily penetrates into the coring tube with corresponding expulsion of the drilling mud initially present therein.

The coring head 1, carrying suitable rotary cutters 2, is threadably attached to the lower end of the rotor shaft 3 of the turbine. The shaft-3 has a generally tubular form and is guided by the bearing 4 in the lower end of the stationary member of the turbine. As shown, this stationary member, or stator, is formed in two parts one being a lower section 5 carrying the guide hearing 4 and the other 6, carrying the fixed turbine vanes or blades 7- 'and being threadably secured at its upper end tothe bottom section of the drill pipe 8. The rotor shaft 3, in that portion thereof that is coextensive with the part of the stationary member 6 that carries the stator blades 7, is provided with cooperating turbine vanes 9-alternating with the stator vanes 7. Suitable radial and axial bearings, not shown, are associated with the bladed section of the'turbine in known manner.

The driving fluid or drilling mud is delivered downwardly through the drill pipe 8 and through an orifice or orifices 35in the member 15 the function of which will be further described. These orifices 35 extend parallel to the axis and carry the fluid into the space 37 within the member or shell 6, this space 37 extending about the' upper end of the rotor shaft 3'. This fluid then passes downwardly through the rotor blades i9 and the stator blades 7, thence through the openings 39 in the shaft 3, continuing downwardly through the annular space 41 and thence through orifices 43 in the coring head 1 to supply the cutters 2 with the drilling mud.

The coring tube extends axially of the turbine within therotor shaft 3 and is constituted by a lower tubular section 10 of suitable length for the core and by an upper tubular section 11, these sections'being connected together by an interposed member 12 which includes a drainage valve more particularly hereinafter described. At' its upper end the tubular section 11 is secured to a member 13 having a tapering seating surface 14 adapted to seat in a' correspondingly shaped seat in a member 15 which is shown as secured to the section 6 of the stationary turbine member adjacent its point of attachment to the drill'pipe. The member 15 may be secured to the section 6 in any suitable manner. As shown the member 15 is provided with a flange 16 adapted to rest on an annular seat intermediate the internally threaded portion 17 ofthe member 6 and the main wall section of the member 6, so that when the tubular section 6 is threaded onto the end of the drill pipe 8, the member 15 is held in fixed position with the flange 16 seated on the annular seat above mentioned. The lower end of the coring tube is guided at 18 in the outlet of the coring head 1. Spring pressed ratchets 19 are mounted near the lower end of the coring tube in position to be urged inwardly toward the core to aid in severing the same from the earth formation upon upward movement of the coring tube when the core is to be severed and withdrawn.

The member 12 is associated with a plug fitting 20 threaded into the open end of a cavity 21 in the member In this-way it is insured that the'pressure on t I 3 plug 20 is provided with a seat 22 for a ball valve 23. In the prior art arrangement the cavity 21 is placed in communication by means of a lateral passage with the annular space 24 between the coring tube and the inner wall of the hollow turbine rotor shaft. 7

According to the present arrangement, instead of establishing communication from the cavity 21 to the annular space 24, a passage 25 is formed axially of the member 12 and establishes communication between the cavity 21 and the space 26 within thehollow section 11 of the coring tube. This space is put in communication with the annular space 27 between the drill pipe and the wall of the bore hole by providing a passage 28 extending axially of the member 13 from the lower end thereof to a point opposite the seating surface 14 thereof within the member where it communicates with a radially extending passage 29 opening into an annular recess 30 formed in the wall constituting a mating seat 31 in the member 15. A passage 32 communicating with the annular recess 30 at one end and with the annular space 27 between the outside of the turbine and the wall of the bore hole is formed in the member 15 and the wall disposed within said tubular shell coaxially therewith for containing the core produced by said drilling head, means connecting the portion of said tube disposed toward said drill pipe to said shell for supporting said core receiving tube from said shell, said tube supporting means providing a passage for flow of the driving fluid therethrough into engagement with said means carried by said rotor member and said shell foreffecting rotation of said rotor member, said tube supporting means including a member supported in fixed relation to and within said shell and a part connected to said tube and cooperating with said member to support said tube on said member, said member and said part having mutually engaging annular seating surfaces extending about said axis and providing for removal of said tube through the opening defined by said annular seating surface of said member, said member and said part providing a passage extending through said engaged annular seating surfacesfrom a point of communication with the interior of said portion of said tube disposed toward said drill pipe to and communicating with an opening in said shell connecting to the space within the bore hole surrounding said turof the stationary section 6 of the turbine that is in fixed engagement with said member 15. It will be understood that the annular recess 30 is necessary to insure communication with the passage 29, whatever he the orientation of the radial passage 29; with respect to the member 15. a t

Fluid tightness between the member 13 and the seat 14 is established by means of rubber gaskets, not shown in the drawing, thus assuring that the circulating drilling mud being forced downwardly through the drill pipe and the turbine is prevented from passing by way of the seat into the passages in the member 13.

When it is desired to withdraw the coring tube with a core that has been formed in the course of the coring operation, the circulation of the drilling mud is stopped, whereupon the coring tube and the core contained therein may be withdrawn by seizing the head member 13. This member is provided with an extension 33 adapted to be engaged by a suitable tool. It will be apparent thatthe member 13 and the coring tube 10, 11 attached thereto may be withdrawn through the drill pipewithout detaching the turbo-corer unit, and likewise, if desired, the coring tube may be returned to its position within the turbo-corer for obtaining a further core section without raising the drill pipe.

Besides the primary advantage of facilitating the displacement by the core of the drilling mud entrapped in the coring tube, it will be understood that the arrangement according to the invention makes it possible to raise the ball valve 23 and lengthen the section 10 of the coring tube with corresponding reduction in the length of the upper section 11 thereof with consequent increase in the length of the core that may be extracted in a given turbo-coring operation without stopping to withdraw the core through the drill pipe. In fact the arrangement makes it possible to place the drainage valve in the head member 13 itself, in which case the separate coring tube section 11 may be omitted entirely.

It will be further understood that various other changes and modifications of the construction may be made without departing from the invention which is not to be deemed as limited otherwise than as indicated by the scope of the appended claims.

I claim:

l. A turbine drilling unit comprising a rotor member capable of carrying a core producing drilling head on said rotor member for rotation by said rotor member, a non-rotating tubular shell extending about said rotor member and adapted to be attached to a non-rotating drill pipe coaxially therewith, said rotor member and said shell carrying means disposed for engagement by the driving fluid for effecting said rotation of said rotor member relative to said shell, a non-rotating core receiving tube bine unit.

2. A turbine drillingunit as defined in claim 1 in which saidtopcningof said member supporting said core receiving tube provides an outwardly and upwardly flaring annular seating surface, said part providing an annular bearing surface on the outside thereof complementary with respect to and engageable with said annular seating surface of said member when said tube is in position supported by said member, said supporting member and said part respectively having radiallyextending passages therethrough communicating with each other and connected to a passage through said shell communicating with the space within the bore hole exterior to said turbine unit, said communicating radial passages extending transversely through said engaged annular seating surfaces and forming part of said passage extending from said point of communication with the interior of said tube.

3. A turbine drilling unit as defined in claim 2 in which said means supporting said core receiving tube provides an annular recess in at least one of said engaged annular seating surfaces, said annular recess communicating with said radial passages for establishing said communication through said passages from said interior of said tube irrespective of the radial orientation of said radially extending portions of said passages one with respect to the other.

4. A turbine drilling unit as defined in claim 1 which comprises drainage valve means providing a fluid receiving cavity interposed between said tube supporting means and the core receiving portion of said tube, said drainage valve means providing passages communicating with said cavity and forming therewith part of said passage extending between the interior of said core tube and said space within the bore hole, whereby drilling mud within the core tube may flow past said drainage valve and through said cavity and through said passages to the space outside said shell within the bore hole.

5. A turbine drilling unit for attachment to the end of a non-rotatable drill pipe comprising a non-rotatable turbine stator of annular form, means connected to said stator and connectible to said drill pipe to support said stator in position coaxially with said drill pipe, a turbine rotor of annular form disposed within said annular stator, means connected to said stator supporting means and engaging said rotor for supporting said rotor for rotation thereof coaxial ly with said axis of said drill pipe, said stator and rotor providing means engageable by a flowing driving fluid and cooperating upon such engagement for efiecting rotation of said rotor on said axis, a coring head carried by said rotor adjacent the end of said rotor along said axis from said drill pipe, said head being of annular form about and coaxial with said axis and providing a central space for passage therethroughofrthe core as said core is formed, a non-rotating core-receiving tube disposed within said stator and rotor of said turbine unit coaxially with and extending along said axis toward said drill pipe from a point adjacent said head, means connecting said core-receiving tube adjacent the end of said tube disposed toward said drill pipe to said stator supporting means for supporting said core-receiving tube in said coaxial position, said tube supporting means comprising a member supported in fixed relation to and within said non-rotatable annular stator, and a part connected to said tube, and cooperating with said member to support said tube on said member, said member and said part having mutually engaging annular seating surfaces extending about said axis and providing for removal of said tube through the opening defined by said annular surface of said member, said member and said part providing a continuous passage extending transversely through said engaged annular seating surfaces from a point of communication with the interior of said core-receiving tube to and connected to an opening in said annular stator communicating with the space within the bore hole surrounding said turbine unit, said member providing a passage extending therethrough along the axis for conveying the driving fluid for engagement with said cooperating stator and rotor means for eifecting said rotation of said rotor.

6. A turbine drilling unit as defined in claim 5 in which said stator comprises a shell connected to and supported by said means connectible to said drill pipe, said shell extending about said rotor coaxially therewith, said means for efiecting said rotation of said rotor comprising turbine blades respectively carried by said shell and by said rotor in interspersed relation to each other to provide for said flow of driving fluid through said blades to eifect said rotation of said rotor.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Article from Oil and Gas Journal, November 1955, pages 977-99, Russians Boast Success for Their Turbodrills. 

